This week's Friday Field Photo is from the Cretaceous of Utah (the Blackhawk Formation of the Book Cliffs to be specific) and shows some very nice cross stratification in fine-grained sandstones.
This photograph is from a field trip I took in the early 2000s when I wasn't nearly as diligent as I am now with taking notes on every photograph I take. I think this is from one of the shallow-marine/shelf units (Kenilworth, Grassy, Desert, etc.) somewhere between the towns of Price and Green River.
If you haven't already seen them, check out these cross bedding visualizations from the USGS. They very nicely illustrate how 3D dune stratification forms.
Happy Friday!
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Image: from my personal collection / © Brian Romans
